Even those passengers who have used Dublin Airport hundreds of times have probably failed to notice one unusual feature; on no single journey are they subjected to both an immigration and security check at the airport.
The situation is the same all over the world. And while the apparent breach at Dublin Airport is a concern, the Dublin Airport Authority, which runs the facility, will now review procedures.
It will need to explain the shortcomings, if any are found, to the Irish Aviation Authority domestically and the International Civil Aviation Organisation globally.
At the centre of the case now highlighted by a Garda inquiry is an allegation that immigration controls were bypassed.
There is no allegation security was compromised in Dublin, because security checks are carried out at the airport of departure rather than arrival.
Airline passengers departing any airport have their passports checked by their airline and, along with their luggage, go through security searching and scanning.
It is only when they arrive at their destination airport that they go through Customs and immigration.
When staff, including those in vehicles, are leaving the landside area and going airside, they are subjected to a security check; including having their identification and clearance levels scrutinised.
Abused
However, once they pass that check and go airside in a vehicle, they can come back landside without being checked again.
Gardaí believe this may have been abused in Dublin.
If an illegal immigrant presented a passport at a foreign airport before boarding a flight to Dublin, the passport would be checked by airline staff for identification purposes only, not for immigration purposes.
The passenger would then be security scanned and searched, and their luggage checked, before being allowed on to their flight to Dublin.
On landing in Dublin, the passenger would be aware they needed to pass through immigration checks.
Without the proper visa, they would be sent back to their airport of origin on the next flight.
But if they were aided illegally by a staff member in a vehicle airside, they could simply hitch a lift in that vehicle and, because that vehicle would face neither security nor immigration checks going back landside again, they could bypass the border into the State.
The many facets of the security, Customs and immigration at Dublin Airport are run by a number of agencies.
Airport Police
About 300 members of the Airport Police work in Dublin, Cork and Shannon airports and have all the powers of the Garda when they are within the airport campus, including the power of arrest.
As part of their remit in detecting and preventing crime, they have the power to request identification from any person or to stop and search anyone, or any vehicle, at the airports.
They are responsible for the general policing of airports in maintaining the peace and safety and also the protection of civil aviation – from planes to the runways and all other infrastructure civil aviation uses to operate.
While they have the power of arrest and to stop and search people – and seize contraband – they must immediately surrender suspects and investigations to the Garda.
Dublin Airport Authority security
The security staff employed by DAA are responsible for operating all of the checks that passengers, luggage and staff go through when going landside to airside.
This includes checking for prohibited items in luggage, concealed weapons and all other contraband to ensure planes and their staff are not under threat.
The security staff are those personnel that pat down passengers who sound the alarm walking through the metal detectors and who scan carryon luggage.
Similar scanning is conducted out of sight on luggage to ensure no explosives or other banned items are hidden away in bags going into the luggage hold of an aircraft.
Garda
Garda members carry out the passport checks for arriving passengers at the immigration booths in Terminal One.
In Terminal Two that function has been civilianised. A new uniformed border management unit has been established by the Irish Naturalisation and Immigration Service of the Department of Justice.
Separately, the Garda’s new armed support unit for Dublin has also been tasked with providing an armed presence at times at the airport.
Other specialist Garda units monitor the movements of suspects, involved in drug dealing for example, using the airport.
Revenue's Customs service
Customs operates overt and covert operations at Dublin Airport. As part of the overt activities, customs officers select passengers for stopping and searching.
They can choose disembarking passengers for searching simply based on their appearance or profiling, which takes into account the routes they have come through.
The Customs officers check for contraband: from drugs to large sums of cash, commercial quantities of cigarettes and alcohol, counterfeit medicines, weapons and a range of other prohibited items.
They also use sniffer dogs to check large quantities of luggage, with the dogs trained to smell cigarettes, drugs and even cash.
